SACRAMENTO – In an election no one could have predicted last summer, voters will go to the polls Tuesday in a special ballot to choose a representative for Riverside County’s 37th Senate District.

John Benoit won the seat in November 2008. Last August, Benoit announced that he was seeking an appointment to the Riverside County Board of Supervisors following the resignation of Roy Wilson, who died days later.

Gov. Arnold Schwarzenegger appointed Benoit to the board in early November. Benoit resigned from the state Senate a few weeks later, and the governor called Tuesday’s special election.

Seven candidates are on the ballot: Three Democrats, three Republicans and one American Independent.

The large lineup makes it unlikely that any candidate will reach the 50 percent threshold needed to win the seat outright.

In that case, the top finisher from each party will advance to a June 8 runoff. That election coincides with the statewide primary ballot.

The sprawling 37th is the only Senate district entirely within Riverside County. It had 462,015 registered voters as of January. Of those, almost 196,000 are permanent vote-by-mail voters or voters in all-mail precincts.